Goldbeating lubricant



Patented July 18, 1944 GOLDBEATING LUBRICANT Donald D. Swift, Hartford, Conn., assignor to M. Swift & Sons, Inc., a corporation necticut of Con- No Drawing. Application October 28, 1939, Serial No. 301,797

v 8 Claims.

My present invention relates to the goldbeaters art and more particularly to an improved lubricant to be used with goldbeaters skin.

In beating gold or other metallic leaf, it is customary to place small squares of gold in a packet. each square between sheets of cutch paper, the entire packet then being beaten until the gold or other metal spreads to the size of the enclosing sheets. The metal is then quartered and the quarters are placed between packets of goldbeater's skin and further beaten. This process is continued until the leaf has reached the desired size and thinness.

The conventional goldbeaters skins are of animal origin, but substitutes such as Cellophane or cellulose acetate may be used. To facilitate the beating operation, it is customary to doctor the goldbeater's'skin or the substitute and to add a suitable lubricant. The conventional doctoring long used for this purpose consists essentially of isinglass, gum arabic, shellac, and spices such as saffron, cinnamon, and cloves in red wine. The lubricant is usually made up from soap, ypsum, and water, or in some instances, alcohol.

I have found that a greatly improved goldbeaters lubricant is obtained by the use of a mineral carrier which is soft enough to be scratched bya fingernail and which can be subdivided to almost microscopic dimensions. have found that the imbedding of such a mineral carrier in a fatty acid sodium salt produces a far cium sulphate, in powder form, is then mixed into the solution; an alkaline earth soap, such as calcium, magnesium or zinc stearate, may be used instead of the calcium sulphate. It is preferred that a uniform mixture be obtained so that the fine particles of the dehydrated calcium sulphate powder or soap are suspended in the solution of the sodium stearate or sodium palmitate in alcohol, the alcohol tending to inhibit hydrolysis of the soap. The alcohol is then evaporated by any suitable, well-,-known method and the residue is a smooth, fine-grained lubricant farsuperlor to any that have heretofore been used. a

It is preferred to use such proportions of the sodium stearate or sodium palmitate and the completely dehydrated calcium sulphate that'the final product comprises particles of calcium sulphate each covered with a surface layer of soap. For example, 6 oz. of sodium stearate are dissolved in about 3 qts. of alcohol. After the soap is completely dissolved, 12 lbs. of completely dehydrated calcium sulphate in a finely powdered form are slowly stirred into the solution. The alcohol is then evaporated.

The resultant lubricant is fine grained, soft, will not scratch or puncture the gold or other metallic leaf during the .beating operation and has very superior lubricating qualities.

While I have described a specific mineral carrier and specific soaps, it is obvious that other carriers and other soaps or their equivalents may be used in varying proportions, without depart= ing from the spirit and the scope of the invention as defined in the appended claims.

I claim:

l. The method of preparing a lubricant for metal beating, comprising the steps of dissolving a fatty acid sodium soap in alcohol, said soap having the characteristics of being soluble in alcohol, nonadhesive, chemically stable and hav ing a high melting point, mixing comminuted particles of calcium stearate therein, and evap crating the alcohol. I

2. The method of preparing a lubricant for metal beating, comprising the steps of dissolv ing a fatty acid sodium soap in alcohol, said soap having the characteristics of being soluble in alcohol, non-adhesive, chemically stable and having a high melting point, suspending comminuted particles of an alkaline earth soap in the solution, said alkalineearth soap being insoluble in alcohol, and evaporating the alcohol.

3; An improved lubricant for metal beating comprising comminuted particles of calcium stearate, each particle being covered by a surface layer of a fatty acid sodium soap soluble in alcohol, non-adhesive, having a fairly high melting point, and chemically stable.

'4. An improved lubricant for metal beating comprising comminuted particles of a metal soap from the group consisting of calcium stearate, magnesium stearate, and zinc stearate, characterized by being insoluble in alcohol, soft enough to be scratched by a fingernail, and capable of microscopic subdivision, each particle being coveredby a surface layer of a fatty acid sodium soap soluble in alcohol. nonadhesive, having a fairly high melting point, and chemically stable.

5. An improved lubricant for metal beating comprising .comminuted particles of calcium stearate, each particle being covered by a surface layer of sodium stearate.

6. An improved lubricant for metal beating comprising comminuted particles 01' calcium stearate, each particle being covered by a surface layer of sodium palmitate.

7. An improved lubricant for metal beatin comprising comminuted particles or a, metal soap from the group consisting of calcium stearate, 

